Re: [PATCH v11 04/14] block/backup: introduce BlockCopyState

[Max Reitz]

On 20.09.19 14:56, Vladimir Sementsov-Ogievskiy wrote:
> 20.09.2019 15:56, Vladimir Sementsov-Ogievskiy wrote:
>> 20.09.2019 15:46, Max Reitz wrote:
>>> On 13.09.19 20:25, Vladimir Sementsov-Ogievskiy wrote:
>>>> 10.09.2019 13:23, Vladimir Sementsov-Ogievskiy wrote:
>>>>> Split copying code part from backup to "block-copy", including separate
>>>>> state structure and function renaming. This is needed to share it with
>>>>> backup-top filter driver in further commits.
>>>>>
>>>>> Notes:
>>>>>
>>>>> 1. As BlockCopyState keeps own BlockBackend objects, remaining
>>>>> job->common.blk users only use it to get bs by blk_bs() call, so clear
>>>>> job->commen.blk permissions set in block_job_create and add
>>>>> job->source_bs to be used instead of blk_bs(job->common.blk), to keep
>>>>> it more clear which bs we use when introduce backup-top filter in
>>>>> further commit.
>>>>>
>>>>> 2. Rename s/initializing_bitmap/skip_unallocated/ to sound a bit better
>>>>> as interface to BlockCopyState
>>>>>
>>>>> 3. Split is not very clean: there left some duplicated fields, backup
>>>>> code uses some BlockCopyState fields directly, let's postpone it for
>>>>> further improvements and keep this comment simpler for review.
>>>>>
>>>>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>>>>> ---
>>>>
>>>>
>>>> [..]
>>>>
>>>>> +
>>>>> +static BlockCopyState *block_copy_state_new(
>>>>> +        BlockDriverState *source, BlockDriverState *target,
>>>>> +        int64_t cluster_size, BdrvRequestFlags write_flags,
>>>>> +        ProgressBytesCallbackFunc progress_bytes_callback,
>>>>> +        ProgressResetCallbackFunc progress_reset_callback,
>>>>> +        void *progress_opaque, Error **errp)
>>>>> +{
>>>>> +    BlockCopyState *s;
>>>>> +    int ret;
>>>>> +    uint64_t no_resize = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE |
>>>>> +                         BLK_PERM_WRITE_UNCHANGED | BLK_PERM_GRAPH_MOD;
>>>>> +    BdrvDirtyBitmap *copy_bitmap;
>>>>> +
>>>>> +    copy_bitmap = bdrv_create_dirty_bitmap(source, cluster_size, NULL, 
>>>>> errp);
>>>>> +    if (!copy_bitmap) {
>>>>> +        return NULL;
>>>>> +    }
>>>>> +    bdrv_disable_dirty_bitmap(copy_bitmap);
>>>>> +
>>>>> +    s = g_new(BlockCopyState, 1);
>>>>> +    *s = (BlockCopyState) {
>>>>> +        .source = blk_new(bdrv_get_aio_context(source),
>>>>> +                          BLK_PERM_CONSISTENT_READ, no_resize),
>>>>> +        .target = blk_new(bdrv_get_aio_context(target),
>>>>> +                          BLK_PERM_WRITE, no_resize),
>>>>> +        .copy_bitmap = copy_bitmap,
>>>>> +        .cluster_size = cluster_size,
>>>>> +        .len = bdrv_dirty_bitmap_size(copy_bitmap),
>>>>> +        .write_flags = write_flags,
>>>>> +        .use_copy_range = !(write_flags & BDRV_REQ_WRITE_COMPRESSED),
>>>>> +        .progress_bytes_callback = progress_bytes_callback,
>>>>> +        .progress_reset_callback = progress_reset_callback,
>>>>> +        .progress_opaque = progress_opaque,
>>>>> +    };
>>>>> +
>>>>> +    s->copy_range_size = 
>>>>> QEMU_ALIGN_UP(MIN(blk_get_max_transfer(s->source),
>>>>> +                                           
>>>>> blk_get_max_transfer(s->target)),
>>>>> +                                       s->cluster_size);
>>>>
>>>> preexistent, but it obviously should be QEMU_ALIGN_DOWN. I can resend with 
>>>> a separate
>>>> fix, it may be fixed while queuing (if resend is not needed for other 
>>>> reasons) or
>>>> I'll send a follow-up fix later, whichever you prefer.
>>>
>>> Hm, true.  But then we’ll also need to handle the (unlikely, admittedly)
>>> case where max_transfer < cluster_size so this would then return 0 (by
>>> setting use_copy_range = false).  So how about this:
>>
>> Done in [PATCH v12 0/2] backup: copy_range fixes.
>> If it is convenient I'll rebase these series on "[PATCH v12 0/2] backup: 
>> copy_range fixes"

Oh, good.

I think taking copy_range fixes first would make more sense.  It seems
that John still had some suggestion for it...?

Max

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